Well , seems that you only read the title and not the whole whitepaper . Look at references 3 and 4 , satoshi pointed there are things that can be done through script ,
When you write a paper you always refer to other work that was done and share similarity with your new work. When Satoshi was explaining what a "timestamp server" is he referred to 4 other works done in that topic (references 2 to 5) in the past. That doesn't mean Bitcoin is meant to be used as cloud storage just because these references exist in the paper!!!
infact he was the first to inject arbitrary data on chain .
And he did it within the protocol rules not by exploiting them. In fact he used the strictest one that allows the miner to insert a tiny message (max 100 bytes) in the coinbase of the block they work hard to find.